Post Date November, 16 2024
In recent years, the prevalence of AIDS in China has shown new characteristics. More than 90% of AIDS cases are sexually transmitted, and the trend is rising rapidly. According to authoritative data, 97000 new cases of AIDS virus infection were found in China from January to October 2015, 14200 of which were teenagers aged 15-24. AIDS has quietly entered university campuses, and the number of newly discovered young students infected has tripled in five years.
How AIDS came into being
Two glycoproteins, gp120 and gp41, are embedded in the lipoproteins envelope of the outer layer of AIDS virus (HIV). gp120 has affinity with CD4 glycoprotein on the surface of lymphocytes and can specifically bind to it; Gp41 mediates the fusion of viral envelope and host cell membrane fusion. Therefore, HIV can selectively invade CD4+lymphocytes after reaching the bloodstream through damaged skin and mucous membranes or through other channels such as blood.
After HIV invades CD4+lymphocytes, it synthesizes DNA under the action of viral reverse transcriptase and integrates into the chromosomes of the host cell. The integrated viral DNA can replicate within the cell, form a complete viral body, and release it out of the cell. The cell dies, infects new cells, and can also be in a latent infection state, entering offspring cells with cell division.
In the early stages of infection, HIV replicates in large quantities, leading to viremia and the expression of capsid antigen p24, presenting clinically as symptoms of acute HIV infection. Due to the extensive intracellular replication of HIV, CD4+lymphocytes are damaged and die, resulting in a significant decrease in CD4+T cells. However, under the immune action of the body, CD8+CTL is activated, killing HIV infected cells, and producing anti HIV antibodies. Viremia is quickly cleared, and the number of CD4+lymphocytes increases.
How many ways can AIDS be transmitted
HIV exists in the blood, semen, vaginal secretions, tears, urine, milk, and cerebrospinal fluid of infected people. AIDS patients and HIV carriers are infectious, mainly through sexual contact transmission, followed by blood transmission, such as drug users, HIV infected blood or blood products, HIV infected blood and mucus.
1. Sexual transmission: AIDS virus can be transmitted through sexual intercourse. When the genitalia suffers from sexually transmitted diseases (such as syphilis, gonorrhea, genital warts) or ulcers, it increases the risk of contracting the virus. There are a large number of viruses in semen or vaginal secretions of people infected with AIDS virus, which can be transmitted through anal and vaginal sexual intercourse. The probability of oral sex transmission is relatively small. Unless the healthy party has a wound in the mouth or a broken place, AIDS virus may be transmitted through blood or semen.
